BMW Australia has cranked up the heat on its X4 range with the arrival of the new xDrive35d, which packs a 230kW/630Nm 3.0 litre turbo six under its bonnet and can zip to 100km/h in a swift 5.2 seconds.

It arrives at a price point that puts it up against the Porsche Macan S Diesel and Audi SQ5, with a bodystyle akin to the former and straight-line go that matches the latter. After a quick stint behind the wheel, the most athletic member of the X4 family definitely proved its worth as a driver’s car.

OVERVIEW

The 35d jumps in as the 30d taps out, meaning those going for BMW’s top-tier diesel X4 now need to pay an extra $5700.

But that extra dosh nets you a 40kW bump in power and 70Nm more torque, a 0.6-second reduction in 0-100km/h time and just a 0.1 l/100km increase in fuel consumption.

The standard spec increase over the 30d also includes keyless entry, internet connectivity, a digital radio tuner, Harman Kardon premium audio and the M Sport package. At retail value, that’s $9300 of extra features.

Along with the petrol-powered xDrive35i, the X45 xDrive35d gets the most generous standard specification out of all X4 models and the interior is certainly well-equipped.

But next to other members of the BMW family it’s starting to look a little dated. The quality of materials is good, but the absence of a tombstone-like infotainment display (it’s instead recessed well into the dash), is the tell-tale sign that this cabin, which is shared with the X3, was designed before the current crop of BMW interiors.

That doesn’t mean it’s no good, far from it. It might be wearing last season’s fashions, but it still looks - and functions - fine. The front seats are supportive, the black headliner gives the cabin a cosy feel and every control falls neatly to hand.

That said, the back seat is compromised by the X4’s tapering “coupe-like” (BMW’s words, not ours) roofline, a styling gimmick that, despite its impact on rear passenger comfort, has proved popular with over 100,000 customers globally.

Headroom is tighter than an X3, and getting in and out is hampered by the smaller door opening. Mind your head, especially if you’re over 5’10”

Ignore the different nomenclature: the X4 xDrive35d’s 3.0 litre turbo diesel six is the same as that in the X5 xDrive40d. It’s got plenty of mumbo in the 2.1-tonne X5, but in the 260kg lighter X4 it makes for a damn quick SUV.

At 5.2 seconds to 100km/h the X4 35d is knocking on the door of AWD hot hatches like the Volkswagen Golf R, but with a 6.0 l/100km combined fuel consumption it’s got the thirst of a camel.

Best of both worlds? Pretty much.

Stomp the throttle and the 35d launches forth like a sports car, with peak torque available from as low as 1500rpm and minimal turbo lag.

The powerband is also quite broad for a diesel, meaning frequent gearchanges aren’t necessary to keep the engine in the butter zone. Just ride that broad plateau of torque and dispatch steep hills with ease.

It’s not too shabby when a set of corners approaches, either. The electrically-assisted steering is nicely weighted and transmits enough feedback to let you know when front-end grip is running out, and the X4’s chassis - enhanced with adaptive dampers in the 35d - is quite nicely balanced.

There’s grip aplenty in the dry, and some moderate rainfall late in the drive programme didn’t do much to shake the X4’s hold on the tarmac.

That said, turn it in too quickly on a rain-slicked corner and you can work the tail loose before the stability control reins it back in. The X4's resistance to understeer is admirable for something that doesn’t bear an M badge on its rump.

It’s sportier than the average mid-size SUV, that’s for sure.

We can’t vouch for ride comfort on the 35d’s standard 20-inch wheels, as the car we drove was equipped with no-cost-optional 19-inch alloys.

The suspension felt fine on those rollers - not too sharp, not too soft - but given every 35d at the launch sported 19-inch wheels we suspect BMW may be trying to obscure something there.

Perhaps approach the 20-inch wheels with caution if you value a supple ride.

SAFETY

RIVALS TO CONSIDER

From a performance standpoint, the BMW X4 xDrive35d roughly equals the Audi SQ5, with identical 0-100km/h sprint times, a sports-tuned AWD system, eight-speed transmission and the same 230kW power output.

The SQ5 (below) has a more passenger-focus, however, with a traditional SUV wagon body that better accommodates people and cargo. If only BMW Australia equipped the X3 with the 35d engine...

The Porsche Macan S Diesel is slower and less powerful, but a closer match to the BMW in terms of packaging. At $91,900 the Porsche has a small premium over the X4, but offers a great deal more brand cachet for those who care about such things.

Other than those two, there are few other sporty choices in the midsize luxury SUV category - the Mercedes GLC 250d doesn’t come close enough in performance or pricetag, nor do the Lexus NX or similarly-priced Infiniti QX70 variants.

TMR VERDICT | OVERALL

Yours truly isn’t a big fan of the X4’s hump-backed styling. It doesn’t quite possess the same butch toughness of the X6, rather looking like that car’s scrawny kid brother.

Still, beauty is in the eye of the beholder and whatnot, so we won’t mark it down for aesthetics. In fact, the only thing we’d really mark it down for is rear seat headroom and a slightly out-of-date cabin. Everything else is hard to fault.

It drives superbly and that engine is one of the best medium-capacity diesels around. Smooth, torquey and fairly quiet, it’s the perfect powertrain for a performance SUV. It’s great in an X5, it’s even better in the lighter, nimbler X4.